Chrysler Repair/Oil light blinks on and off: '09 3.5L

QuestionI have a 2009 chrysler 300 3.5L
The last two days my oil light comes off and on and dings every minute or so Just got my oil change and was hoping it would stop but still having the same problem. The car does have about 116k. What can I do to fix this????

AnswerHi Venise,
The oil pressure warning is supposed to occur if the oil pressure is below 5 pounds per square inch. The specifications are that the oil pressure should be higher than 5 at engine idle speed, and then at 3,000 rpm speed it should be 45 to 105 psi (though there is no warning if it isn't that high).
The pressure is dependent upon the condition of the engine and also upon the viscosity of the engine oil. What viscosity of oil was in use prior to the change, and what viscosity was used at the recent oil change. The number is supposed to 5W-30 or higher. If lower than that, say 0W-40 then that may explain a lower than specified pressure and you could then return to the oil change shop and have the viscosity increased (and perhaps not charge you if they used too low a viscosity fluid). If they used 5W-30, then you could change to 10W-40 at the next oil change to then eliminate the alarm for that will raise the pressure at idle speed to more than 5 psi in all likelhood. But also consider, If that is not the reason:
It may be that the pressure sender unit is inaccurate or that it is leaking oil and thus reading lower than the actual pressure. So one would simply inspect the sender unit which is located immediately above the oil filter, on the front of the engine just to the right of the crankshaft pulley. Be sure it is dry of oil residue not dripping when the engine is idling.
Then if that checks out, the accuracy of the sender can be verified by removing the sender and inserting an actual pressure gauge in the hole and see what that reads at idle and at 3,000 rpm.
Then based upon that one would know if the sender was accurate and whether the oil pressure specification was acceptable.
So those would be the steps I would suggest to find out what is the cause of the pressure warning you are experiencing.
If the alarm only occurs at idle, I would not be alarmed. However, if the alarm occurs when the engine is operating above idle rpm then that would be important to deal with this promptly as the engine could be otherwise seriously damaged.
So let me know what you learn and tell me whether the alarm sounds at any time other than when the engine is idling.
Roland
PS Thanks for the rating and nomination.